If you try to trade it at Gamestop/Eb Games you will most likely get ripped off, they may accidentally give you half of what was quoted above. A big reason why, is that there is no market for an original Xbox and they would have to try to resale it. You would be better off selling it yourself...try ebay, you might can get close to $200 USD for all that.

A few days ago I was at Gamestop (the ebgames name is gone now here) and 4 different people came in to trade in their xbox with two controllers. The were given $45us. If they had wanted cash it would have been $25.

I say, sell the games and turn the xbox into a media center PC. It's easily doable with Linux. Put a bigger HDD in it and have fun.